19 May
2007
19 May
'07
10:35 a.m.
"Glen Slick" <glen.slick at gmail.com> skrev:
On 5/17/07, Rod Smallwood <RodSmallwood at
mail.ediconsulting.co.uk> wrote:
Correct. So if people could stop assuming that an 11/84 have a q-bus, we
would get a long way towards clearing this up.
If people don't know about the 11/84 or 11/94, don't write answers based
on your knowledge of the q-bus based KDJ11 setups.
> OK we have a change
>
> > >PMI memory goes in slots 1 and 2, CPU goes in 3
> > >joe lang
>
> Rod
>
From my understanding of this after looking at various manuals this is
true for an 11/73 or 11/83 with an H9872 backplane in a BA23 box, but
not for an 11/84. Figure 8-6 in EK-PDP94-MG-001_Sep90.pdf shows a
PDP-11/84-A backplane
with the MDM M7677 in the MDM slot, the KDJ11-BF M8190 in slot 1, a
MSV11-JB/JC M8637-BA/CA in slot 2, and a MLM load module M7556 in slot
3. Not clear to me if the MLM in this case could be replaced by a
second MSV11-J.
Yes. The MLM isn't really neccesary if you have one memory card in there
either, if I remember right. But if you have two memory cards, you don't
have any space left for the load module anyhow.
The 11/94 backplane shown in figure 1-2 in
EK-PDP94-MG-001_Sep90.pdf
shows a KDJ11-E M8981 in slot 1, an APS module M7914 in slot 2, and
slot 3 empty. Does anyone know for certain that this backplane it
compatible with MSV11-J modules, and if so in which slots they would
go?
It's the same backplane. I have an 11/94 box here with an 11/84 cpu and
memory. Works just fine.
Just wish I could land an 11/9x cpu as well. :-)
Johnny
--
Johnny Billquist || "I'm on a bus
|| on a psychedelic trip
email: bqt at softjar.se || Reading murder books
pdp is alive! || tryin' to stay hip" - B. Idol
20 May
20 May
5:28 p.m.
On Saturday 19 May 2007 06:35, Johnny Billquist wrote:
Correct. So if people could stop assuming that an 11/84 have a q-bus,
we would get a long way towards clearing this up.
If people don't know about the 11/84 or 11/94, don't write answers
based on your knowledge of the q-bus based KDJ11 setups.
My "11/94" (which was an upgraded 11/84, and which I got CPU-less)
actually does have a QBUS... it's got an Able Qniverter to hook the
UNIBUS in the chassis to the QBUS from the CPU, and both QBUS and UNIBUS
peripherals.
Does anyone know how common that was? I don't see any evidence pointing
towards it not being designed that way by DEC. The chassis is DEC
badged, with a label on the side indicating that it was upgraded from an
11/84 to be an 11/94 at some point.
Pat
--
Purdue University ITAP/RCAC --- http://www.rcac.purdue.edu/
The Computer Refuge --- http://computer-refuge.org
"Glen Slick" <glen.slick at gmail.com>
skrev:
> On 5/17/07, Rod Smallwood <RodSmallwood at mail.ediconsulting.co.uk>
wrote:
> OK we have a change
>
> > >PMI memory goes in slots 1 and 2, CPU goes in 3
> > >joe lang
>
> Rod
From my understanding of this after looking at various manuals this
is true for an 11/73 or 11/83 with an H9872 backplane in a BA23
box, but not for an 11/84. 
5:31 p.m.
On 19/05/2007 11:35, Johnny Billquist wrote:
"Glen Slick" <glen.slick at gmail.com>
skrev:
>>> > >PMI memory goes in slots 1 and
2, CPU goes in 3
> From my understanding of this after looking at
various manuals this is
> true for an 11/73 or 11/83 with an H9872 backplane in a BA23 box, but
> not for an 11/84.
BA23 is H9278, actually.
Correct. So if people could stop assuming that an
11/84 have a q-bus, we
would get a long way towards clearing this up.
Except that it does have a (short) QBus :-)
OK, we're agreed that the standard config for an 11/83 puts the memeory
before the processor, and the standard config for an 11/84 puts the
memory after the processor :-)
Slots 1 to 3 of the H9277-A in an 11/84 *are* Q-Bus, and just the same
as slots 1 to 3 in the H9278-A in a BA23 box, except that instead of the
connections on sections C and D merely connecting the lower surface of
one slot to the upper surface of the next, they're bussed right through,
on the upper surfaces of both C and D. You can see that from the 11/84
technical documentation. Of course the topmost slot is dedicated to the
MDM, slot 4 is dedicated to the KTJ11 which converts one bus to t'other,
and the lower slots (5-12) are Unibus.
This is why it's not necessary to put the PMI memory in front of the CPU
in an 11/84 backplane. It is necessary in an 11/83 backplane because
the KDJ11 only has the CD-interconnect on the upper surface (ie on
fingers Cx1 and Dx1). Therefore it will not get any PMI control signals
from a PMI board placed below it in a BA23 or BA123
backplane. It's
this bussing of the PMI control signals on C/D which differs,
not the
QBus part, which PMI uses for the data, address, and some of the basic
control signals. PMI memories like the MSV11-J complete the bus on the
C/D fingers of a BA23 by having their Cx1 connected to their Cx2 (and
Dx1 to Dx2).
The P-series 11/84 which I've found described in one of the later 11/84
manuals used an MSV11-R, which is a normal QBus memory, not PMI.
The above does *not* mean you could just put any QBus card into an
11/84. Obviously devices meant for Q22-Q22 serpentine backplanes would
not work (and would potentially cause damage), devices with 16-bit and
18-bit addressing wouldn't work fully (if at all), and even some
quad-height cards that normally use Q22-CD backplanes could be a
problem, because many of them put test signals on the C or D fingers,
and that would upset the PMI. I wouldn't recommend putting anything in
an 11/84 that DEC didn't intend.
--
Pete Peter Turnbull
Network Manager
University of York
6443
days inactive
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